Experimental and theoretical investigations of a plasma fireball dynamics

Abstract

Periodic current bursts observed in the dynamic current-voltage characteristic of a probe in the presence of a plasma fireball in dynamic state were modeled in the frame of the scale relativity model, based on both the fractal space-time concept and the generalization of Einstein’s principle of relativity to scale transformations. The bursts appear in the probe characteristic when a certain relation exists between the fireball dynamics frequency and the frequency of the probe voltage sweep. The double layer dynamics is described by a set of time-dependent Schrödinger-type equations and the self-structuring is given by means of the negative differential resistance. The obtained experimental and theoretical results are proven to be in very good agreement.

Solid components separation from heterogeneous mixtures through turbulence control

“…Here, the mixed modes theoretically described in the above sections were experimentally observed in a complex low-temperature plasma in which a space charge structure develops in form of a fireball [63,[74][75][76][77][78]. The fireball was produced by positively biasing a tantalum disk electrode with 1 cm in diameter, introduced into a discharge plasma under the following experimental conditions: argon pressure p = 7 × 10 −3 mbar, plasma density n pl ≅ 10 8 − 10 9 cm −3 and the electron temperature kT e = 2 eV [74][75][76][77][78].…”

“…The fireball was produced by positively biasing a tantalum disk electrode with 1 cm in diameter, introduced into a discharge plasma under the following experimental conditions: argon pressure p = 7 × 10 −3 mbar, plasma density n pl ≅ 10 8 − 10 9 cm −3 and the electron temperature kT e = 2 eV [74][75][76][77][78]. The fireball suddenly appears in front of the electrode at a critical value of the voltage applied to it V E = 85 V, being in adynamic state, fact emphasized by the presence of the oscillations of the current collected by the electrode (see Fig.…”

Moderate Deviations for Stochastic Fractional Heat Equation Driven by Fractional Noise

“…There are also many works about MDP about stochastic (partial) differential equations; some surveys and literatures could be found in Budhiraja et al [11], Wang and Zhang [12], Li et al [13], Yang and Jiang [14], and the references therein. On the other hand, fractional equations have attracted many physicists and mathematicians due to various applications in risk management, image analysis, and statistical mechanics (see Droniou and Imbert [15], Bakhoum and Toma [16], Levy and Pinchas [17], Mardani et al [18], Niculescu et al [19], Paun [20], and Pinchas [21] for a survey of applications). Stochastic partial differential equations involving a fractional Laplacian operator have been studied by many authors; see Mueller [22], Wu [23], Liu et al [24], Wu [25], and the references therein.…”

Spectral investigations of two simultaneous fireballs in plasma

“…At higher values of the applied voltage, two situations were experimentally recorded. In the first case, the fireball passes into a dynamic state, consisting of periodic disruptions and re-aggregations of the double layer, giving rise to oscillations of the current collected by the electrode [4][5][6]. In the second case, a more complex structure develops in front of the electrode, consisting of several concentric luminous shells (like an onion), known as multiple double layer [7][8][9].…”